The Incapacitation of the Dangerous Offender: A Statistical Experiment

Wilson and van den Haag, in particular, have proposed a crime prevention and control approach based on the principle of incapacita tion. By incapacitation, these writers, and others, mean the mandatory imprisonment of career and repetitively violent offenders for lengthy periods. Such an approach, at the very least, would preclude the commission of street crimes by careerists for specified lengths of time.

Several studies have attempted to validate the incapacitation model. Estimates of reduced crime as a result of incapacitation range from an improbable 80 percent to under 10 percent. These estimates are based on various assumptions and in not even one previous study were data collected specifically to test this model of crime prevention.

This investigation represents a focused empirical attempt to evaluate the effectiveness of the incapacitation strategy. The study involved the universe of adult offenders who had been indicted for violent crimes in Franklin County, Ohio in 1973. We tested a series of hypothetical sentencing policies from the most stringent—a five year mandatory sentence on any prior felony conviction, whether violent or not—to far lighter sentences to determine the effects of adult incapacitation-oriented policies on this cohort of violators. The results suggest that the most stringent option would have prevented no more than 4.0 percent of the violent crimes in Franklin County in 1973. The reasons for this minimal impact of the incapacitation strategy are discussed. A short note suggests the impact of extending incapacitation policies to the juvenile system.

1. The cohort consists of all violent felony cases completed in 1973. Not all the cases began in 1973. Half the individuals were first booked in 1973 (50.0 percent), most of the rest in 1972 (45.6 percent) and the remainder in 1971 or before (4.4 percent). For simplicity in the study, the population is called the 1973 cohort and treated as if all cases began in 1973. This determination does not influence the re sults of the study, since the hypothetical in capacitation sentence is imposed on each per son's record individually.